Interaction of Radiation with Surfaces and Electron Tunneling · 9.2.2.1 Metals

This chapter discusses scanning tunneling microscopy (STM) images of metals including silver (Ag), aluminum (Al), gold (Au) and platinum (Pt). Elements are ordered alphabetically and surfaces are listed in order of increasing sum of Miller indices. The roughening transition on the Ag(115) surface has been studied using STM. The STM images directly reveal the shape and nature of the step edges, thereby allowing an unambiguous determination of the roughening temperature. The STM images of the close-packed Al(111) surface revealed a hexagonal array of protrusions varying in height between 0.1 and 0.4 Å, separated by 3.0 Å. STM to study the transition between the high-temperature "1 x 1" and the low-temperature 1 x 2 reconstructions of the Au(100) surface is stated. More recent measurements of STM of Au(111) show that atomic resolution can also be achieved at the higher tunneling resistances of 10⁹ Ω conventionally used in STM. Annealing the surface of Pt(100) to temperatures higher than 1100K results in a rotated hexagonal structure in LEED. STM images of the Pt(100) taken over a wide range of applied bias voltages reveal no significant change in the images, indicating that the observed structure is primarily associated with the surface topography and not due to localized electronic states. STM images of the Pt(110) surfaces are consistent with the "missing row" reconstructions.